[U-Boot] DWMMC crontroller in Exynos4412

Humberto López León
2015-08-26T13:40:06Z

Hi community,

thank you all for answering my questions.

On 08/26/2015 02:53 AM, Przemyslaw Marczak wrote:
> Hi,
>
> On 08/26/2015 08:23 AM, Jaehoon Chung wrote:
>> On 08/26/2015 11:26 AM, Simon Glass wrote:
>>> +Samsung people
>>>
>>> Hi,
>>>
>>> On 25 August 2015 at 13:10, Humberto L?pez Le?n <humberto@uclv.cu>
>>> wrote:
>>>> Hi Simon,
>>>> I'm working on implementing a driver for SD/MMC cards in the framework
>>>> GenodeOS. I think you could help me with your experience in this
>>>> type of
>>>> implementation in the u-boot.
>>>> The hardware platform on which the driver will work is a ODROID-x2
>>>> (exynos4412). I use the DWMMC contoller, but I'm not sure if this
>>>> is the
>>>> right controller to handle SD/MMC cards in Exynos4412 SoC. The SDHCI
>>>> controller is most appropriate?
>>
>> If you're using exynos4412 board, you can choose sdhci or dwmmc
>> controller for eMMC, not SD/SDIO.
>> And in my experiment, dwmmc controller is more appropriate than
>> sdhci.(ex, performance)
>>
>
> It depends which mmc channel is used. In Exynos4412, there are 5
> channels, but some channel configurations shares GPIO pins:
> - MMC0 - sdhci
> - MMC1 - sdhci, or MMC0 8-bit
> - MMC2 - sdhci - Odroid SD card, 4-bit mode
> - MMC3 - sdhci - or MMC2 8-bit
> - MMC4 - dwmmc, uses MMC0 pins for 4-bit, and MMC0-1 for 8-bit mode
>
> Odroid is using MMC2(sdhci) and MMC0/4(sdhci or dwmmc).
>
> So for eMMC cards you can use the dwmmc, and as Jaehoon wrote it is
> recommended for the better performance, but for SD card you must use
> sdhci controller.
This information is valuable to me, but now I would help if you tell me
where I can find the code of SDHCI controller for the SD card of
Exynos4412 in U-boat 2015.04-rc2 for a implementationtation reference.
I was reviewing the file exynos_dw_mmc.c as reference of DWMMC driver,
but now I have no idea what the file where the SDHCI driver for the
exynos4412 is implemented.

Thank you very much for your collaboration.